Riticulatum groupWere generally smaller in stature than other hybrids, evergreen, and featured a white or yellowish stripe down the midrib of the leaf H. riticulatun var. striatifoliumH. riticulatun var. striatifolium 10

American: the late nineteenth to early twentieth centuries (Reginae, Leopodii)– Faded due to disease, competition, and failures in quality control, much of this germplasm was lost.

Europe: declined—the two world wars

11

Netherland—today is the center of modern amaryllis production and breeding.– Large-flowered Ludwig cultivarsLudwig cultivars

--Gracilis dwarf, multiflora typesGracilis cultivars

White Christmas Apple Blossom Gracilis12

South Africa has also become an important breeding center and exporter of amaryllis.

breeding and ploidy levelThe majority of Hippeastrum species are diploid, with a somatic chromosome number of 2n=22.

Virtually all the complex hybrid materials presently in cultivation are tetraploid.

a few species of Hippeastrum have been reported with higher ploidy levels than 4n.

15

The concertration of recent commerical breeding efforts among the various populations of tetraploids may exist for several reason:1.Desirable characteristics of flower size, scape number, and plant vigor are already stabilize in the hybrid races.

2.Sterile triploid progeny result when diploid species are crossed with tetraploid hybrids.

3.Many of the diploid species are not readily available.

4.self-incompatibility, which occurs in most diploid species and diploid hybrids, generally breaks down in the tetraploid hybrid.16

( 1 2 3 4

) novel trait 18 F1

1

2 Leopoldii group17

10

2n=2x=22

2n=4x=44

0x

1x

2x

2x

4x

0x

3x

1x

3x

4x

18

1.

diploid X tetraploid

Sterile (selfed and crossed)

2.Triploid X diploid

embryo rescue

3.Triploid X tetraploid perhaps due to some degree of random assortment of the third set of chromosomes during gamete formation

19

(1.Readily self-pollinated 2.Intercrossed

)

3.Easiest breeding program This has largely been the source of today 's commercial amaryllis cultivars.